1. Field of the Invention
This invention relates to a function adding system for adding a new function to a home electronic device or an incorporated device such as measuring device, and particularly to a function adding system capable of adding a function irrespective of the resources of the device.
2. Description of the Prior Art
Conventional function adding systems for adding a new function to a home electronic device or an incorporated device such as measuring device are disclosed in the following related-art references:                JP-A-05-028120;        JP-A-07-182294;        JP-A-2000-089941;        JP-A-2002-078036; and        JP-A-2002-215298.        
FIG. 1 is a structural block diagram showing an example of conventional function adding system for adding a new function to a home electronic device or an incorporated device such as measuring device.
In FIG. 1, a control unit 1 for controlling an entire device such as a central processing unit (CPU), an input/output unit 2 such as display unit, switch or wireless remote controller, a storage unit 3 in which a program to be executed is stored, a storage unit 4 for work in which a file or the like is temporarily stored when executing the program, a general-purpose network 100 such as the Internet or local area network (LAN), and a storage medium 101 such as flexible disk or compact disc read-only memory (CD-ROM) are described.
The control unit 1, the input/output unit 2, the storage unit 3 and the storage unit 4 form a device 50 that is an incorporated device.
An input/output of the input/output unit 2 is interconnected with the control unit 1. Also inputs/outputs of the storage unit 3 and the storage unit 4 are interconnected with the control unit 1.
The operation in the conventional example shown in FIG. 1 will now be briefly described. When started, the control unit 1 performs initialization of the device 50 as it is necessary, and reads out and executes the program stored in the storage unit 3.
The control unit 1 controls the input/output unit 2 according to the program that is being executed. When executing the program, the control unit 1 also prepares a temporary file or the like and properly stores it into the storage unit 4, if necessary, and thus operates the device 50.
However, in the device 50 as shown in FIG. 1, the program is incorporated in the device. Therefore, in the case of correcting trouble of the program or adding a function, the program stored in the storage unit 3 must be modified or another program must be added.
The operation of adding a function in the conventional example shown in FIG. 1 will be described with reference to FIG. 2. FIG. 2 is a flowchart for explaining the procedure to add a function.
At “S001” in FIG. 2, it is judged whether addition of a function to the device 50 is necessary or not. If it is judged that addition of a function is necessary, it is judged at “S002” in FIG. 2 whether the program in the storage unit 3 of the device 50 is rewritable or not.
If it is judged at “S002” in FIG. 2 that the program in the storage unit 3 is rewritable, an additional program is written to the storage unit 3 at “S003” in FIG. 2.
For example, the additional program is written to the storage unit 3 via the network 100 or written to the storage unit 3 via the storage medium 101.
On the other hand, if it is judged at “S002” in FIG. 2 that the program in the storage unit 3 is not rewritable, the storage unit 3 of the device 50 is replaced with a storage unit in which an additional program is already written, at “S004” in FIG. 2 (i.e., read-only memory (ROM) replacement is performed).
However, in the addition of a function in the conventional example as shown in FIG. 1, the resources of the device 50, which is an incorporated device, such as the storage capacity of the storage unit 3 and the processing speed of the control unit 1, are limited in many cases in order to reduce the cost. Therefore, the resources of the device cannot cope with addition of a function that requires resources exceeding the processing speed and the storage capacity that are not anticipated at the time of manufacturing.